Extruding machine



Aug. 29, 1950 J. E. ROBERTS EXTRUDING MACHINE 2 Sheets-Sheet 1 FiledDec. 29, 1947 ATTOANEY 1950 J. E.IROBERTS 2,520,337

EXTRUDING MACHINE Filed Dec. 29, 1947 2 Sheets-Sheet A 7' TOR/VEYPatented Aug. 29,1950

UNITED STATES PATENT OFFICE EXTRUDING MACHINE .l'ohn E. Roberts,Philadelphia, Pa., assignor to Ralph C. Parlres, Philadelphia, Pa.

Application December 29, 1947, Serial No. 795,159

6 Claims. 1

My invention relates to an extruding machine of the type used for forminviscous or plastic material into predetermined shapes havingpredetermined dimensions preparatory to drying or other processing ofsuch materials.

One object of the invention is to produce an improved drying machine.

In the art of extruding materials of the character described, it isnecessary to avoid over compression of the material so as not to disturbits homogeneity. For example, in some instances, if the material issubjected to pressure exceeding a critical point, the liquid content ofthe material may be squeezed out In other cases the over-compression ofthe material will result in building up resistance which will retard oraltogether prevent passage of the material through the prescribedorifices. In still other materials over compression may otherwiseadversely affect the texture, consistency or other characteristics ofthe material.

It is therefore a further object of the invention to produce an improvedextruding machine by means of which various viscous materials may beextruded in a continuous manner and without any adverse efiects on theconsistency or other characteristics of such materials.

These and other objects are attained by my invention as set forth in thefollowing specification and illustrated in the accompanyin drawings inwhich Fig. 1 is a side elevational view of an extruding machineembodying the invention.

Fig. 2 is a section on line 22 on Fig. 1.

Figs. 3, 4 and 5 are enlarged, fragmentary sections, looking in thedirection of line XX on Fig. 2, illustrating the manner of operation ofthe extruding machine.

The machine illustrated is supported on a pedestal or other suitableframe work H3 and includes a hopper l2 for receiving the material to beextruded. The hopper includes front and rear walls I4 and 16, side wallsl8 and a substantially semi cylindrical bottom wall 20 havingperforations 22 therein. The machine also includes a roll 24 which isexcentrically mounted on a shaft 26 to which it is keyed as at 28 Theshaft rotates in bearings carried by the side Walls l8 of the hopper andis driven by a belt 30 engaging a pulley 32 carried by one end of theshaft. The belt 30 is driven by any source of power, not shown.

Coacting with the roll 24 is an elongated plunger 34 which is of thesame length as the roll and which is carried by the piston 36 of an aircylinder 38 supplied with compressed air from a tank or the like All. IThe plunger is preferably square or rectangular in cross section, sothat the front edge thereof, which has following contact with thesurface of the roll, acts as a wiper and so that the outer vertical faceof the plunger slides vertically against the inner face of the rear wall[6 of the hopper as clearly shown in the drawings.

The apparatus thus far described operates as follows the roll 24 iscaused to rotate at the desired speed and the material to be extruded isfed to the hopper above the roll. Due to the excentric mounting of theroll, the peripheral portion 42 thereof which is farthest from thecenter of the shaft 25 will have a wiping contact with successiveportions of the interior of the semicylindrical bottom wall 28. Forexample, when the roll 24 is in the dotted line position of Fig. 3, theportion 42 of the roll has a wiping contact with the rear wall of thehopper and the opposite portion 433 which is nearest the center of thedrive shaft 26 will be at maximum distance from the front Wall of thehopper, This permits the material to be extruded to move, in thedirection of the arrow in Fig. 3, into the lower portion of the hopper.As the roll rotates in clockwise direction, past the solid line positionof Fig. 3 to the position of Fig. 4, the portion d2 of the roll comesinto wiping contact with the front wall of the hopper. By this means theflow of material into the round bottom of the hopper is cut off and themovement of the roll, from the position of Fig. 4 to the position ofFig. 5, spreads the material which has entered into the lower portion ofthe hopper into a relatively thin film which is easily extruded throughthe holes 22 as the roll moves past the bottom wall 20 of the hopper. Asthe roll moves from the position of Fig. 5, its periphery movesprogressively further away from the front wall of the hopper untilmaximum distance is reached in the position of Fig. 3. In other wordsthe movement of the roll relative to the front wall of the hopper issuch as to simulate the action of a valve which prevents entry ofmaterial into the lower portion of the hopper until the material whichhad previously entered has been extruded. It will be noted that theplunger 34, under action of compressed air, or other yielding, hydraulicor mechanical means, has a following contact with the rear wall iii ofthe hopper and with the periphery of the roller. This prevents thematerial which is in the space below the roll, as shown in Fig. 4 fromescaping between the roll and the rear wall It of the hopper before theroll has reached the position of Fig. 5 and has forced the materialthrough the holes 22, The following plunger 34 thus provides thenecessary pressure component to effect the extrusion of the material. Inorder to prevent over compression of the material, the plunger issubjected to adjustable yielding pressure such as that produced bycompressed air, by hydraulic cylinders or by mechanical springs. Thispermits adjustment according to the characteristics of differentmaterials and permits the plunger to yield and allow the escape ofmaterial between it and the roll, if for any reason, pressure, beyond apredetermined value, should develop between the roll and the lowerportion of the hopper.

The manner in which the roll coacts with the front wall of the hopper tospread the material into a relatively thin film before the material isextruded, results from its excentric mounting on its axis of rotationand is an important feature of the invention because, when the materialis thus spread thin, it can be forced through the Openings 22 with muchless pressure than would be required the material to be extruded was inthe nature of a relatively thick lump or layer interposed between apressure exerting member and a perforated member. If the material is notspread thin, it will take increased pressure to force it through. theperforated bottom of the well and this increased pressure expresses someof the liquid content of the material. The loss of liquid from thematerial hardens it and for all practical purposes it becomes impossibleto extrude the material. In addition, the loss of liquid damages thetexture of the material. Also, the wiping con-- tact between the frontedge of the plunger 3d and the periphery of the roller preventsaccumulation of the material on the roll by scraping such material asmay tend to adhere to the roll and forcing it back into the space belowthe roll shown in Fig. 3.

It will be seen from the foregoing that by the apparatus described,viscous or plastic materials are extruded in a substantially continuousmanner. by first being formed into a relatively thin film and thenforced through the desired holes under controlled, and therefore optimumpressure.

If desired, a belt or other conveyor it may be placed below the hopperfor receiving the extruded material and conveying it to a dryingchamber, or to other processing apparatus, not shown.

In certain cases it may be desirable to provide means for agitating orkneading the material as well as for assisting in the feeding of thematerial to the lower portion of the hopper. To this end, I provide astationary rod t3 carried by the side walls of the hopper and havingspaced fingers 55, and a shaft journalled in the side walls of thehopper and having fingers fi l which interleave with the fingers to Theshaft 52 may be rotated by a belt 55 which derives power from the shaft26 and which engages a pulley 58 on one end of the shaft The rotarymovement of the fingers be through the material fed into the hopper, incooperation with the fixed fingers 5e produces a kneading action andserves to force the material. downwardly between the front wall of thehopper and the roller when the latter is spaced rom front wall duringmovement of the roller f om the position of Fig. 5, through thepositions of 3 and to the position of Fig. 4.

What 1' claim is:

1. An extruding machine including a wall defining a rounded well, atleast a portion of the bottom of said well being perforate, an excentricroll mounted for rotation within said well, means for rotating saidroll, the axis of rotation of said roll being so located relative to thecurvature of the well and the diameter of said roll relative to thediameter of said well being such that the peripheral portion of the rollnearest its axis of rotation will always be spaced from the interior ofthe well to permit introduction into the well of the material to beextruded, and so that the peripheral portion of the roll farthest fromits axis of rotation will have a wiping contact with successive portionsof the interior of the Well to spread the material in the well into arelatively thin film and to extrude the material through the perforateportion of the bottom of said well, a hopper above said well, and aplunger mounted for sliding movement against a wall of said hopper andhaving the edges thereof in constant contact with said roll to preventescape of material between the roll and the hopper wall.

'2. The structure recited in claim 1 and means for applyingpredetermined yielding pressure on said plunger to prevent escape of thematerial being extruded, past the plunger, as long as the pressure onsaid material is less than said yielding pressure.

3. An extruding machine including a wall structure defining a wellhaving its top open and having its lower portion rounded, at least aportion of the bottom of said Well being perforated,

an excentric roll mounted for rotation within said well, and means forrotating said roll, the axis of rotation of said roll being so locatedrelative to the curvature of said well, and the diameter of said rollrelative to the diameter of the rounded portion of the well being suchthat the peripheral portion of the roll nearest its axis of rotationwill always be spaced from the interior of the well to provide room forreceiving the material to be extruded, and so that the peripheralportion of the roll farthest from its axis of rotation will have wipingcontact with the bottom of the well to extrude the material through theperforate portion of the bottom of the well.

4. The structure recited in claim 3 together with a plunger movabletoward and away from the axis of rotation of the roll and havingconstant contact with the roll and with the juxtaposed wall of the well.

'5. The structure recited in claim 4 together with means for forcing thematerial to be extruded into the lower portion of the well between theperipheral portion of the roll which is nearest its axis of rotation andthe opposite wall of the well.

6. The structure recited in claim '3 together with means forintermittently forcing the material to be extruded into the lowerportion of the said well between the peripheral portion of the rollwhich is nearest its axis of rotation and a wall of said well.

JOHN E. ROBERTS.

REFEREN CITED The following references are of record in the file of thispatent:

UNITED STATES PATENTS Number Name Date 1,909,228 Sizer -i May 16, 19332,128,651 Kohler Aug. 30, 1938 FOREIGN PATENTS Number Country Date415,514 Germany Jan. 21, 1921 123,983 Austria July 25, 1931

